comment to the original OP's wanting a defect number:
there is no number because it varies all over the place. a defect is a multi dimensional concept when Apple makes MILLIONS of iPhones per year. Hypothetical question; would you accept a 10% defect rate if it created 2.01% more revenue? Is a failure critical (cause a health hazard) or can the failure be remediated by a future firmware update.
-For a trillion dollar company Apple should have more product situations.
-Might be a good time to take the billionaire peeps wearing tight jeans off stage. Apple has never been an open visible operation anyway. Have you noticed there is a whole media industry that does a beat down down of new Apple released products?